please give me answer of these questions
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Answer:
(i) As a consequence, all liquid surfaces, in the absence of any other external force, tend to contract. Since a sphere has got the minimum surface-to-volume ratio, falling liquid drops are always spherical in shape. In the case of bubbles also, it is surface tension that plays a major role in determining their shape.
(ii) Blotting paper has a large number of pores ( tiny holes ) on its surface. Each pore acts like a capillary tube. When a drop of ink is placed on a blotting paper, it spreads on the paper due to capillary action.
(iii) Actually, evaporation is a cooling process because when liquid turns to gas, it needs more energy and so it has to take that energy from its surrounding. The energy is in the form of heat and when the energy ( heat ) leaves with the evaporating liquid; surrounding gets cooler.
(iv) The temperature remains constant during boiling of water even though heat is supplied constantly because all the heat energy provided is used up in changing the state of water from liquid to gaseous water vapour.
(v) Honey has more strong intermolecular attractive forces than water, so the particles are strongly bound in honey than in water. Hence honey is more viscous than water.
(vi) Mercury does not wet glass - the cohesive forces within the drops are stronger than the adhesive forces between the drops and glass. When liquid mercury is confined in a tube, its surface (meniscus) has a convex shape because the cohesive forces in liquid mercury tend to draw it into a drop.